LMMS + Carla macOS specific issues

[falkTX]

• Mouse events pass-through MDI windows when carla is loaded
• LMMS is not able to restart (not reproducible on CLI)
• Create new carla-plugin.so file (and pkg-config) for others to link to (or figure out something better)

[falkTX]

mouse events-pass through identified to not come from carla, no idea still what happens sadly.

LMMS not being able to restart seems to be caused by carla.

[tresf]

Mouse events pass-through MDI windows when carla is loaded

Duplicate of LMMS/lmms#4183. Upstream reported here: https://bugreports.qt.io/browse/QTBUG-69343?attachmentOrder=desc

[falkTX]

thanks for the confirmation!
so just 1 last issue left to do (besides getting lmms to build with the new carla stuff, but that is outside of carla now)

[tresf]

Mouse events pass-through MDI windows when carla is loaded

FYI, patched downstream by removing the call to winId().

[falkTX]

after some stupid long hours debugging, issue was found and fixed.
no more tickets left for 2.0-RC1! \o/